MASS FLOW METER FOR FLOWING MEDIA, EQUIPPED WITH CORIOLIS FORCE MEASURING SYSTEMS

摘要

The flow meter of the invention comprises at least one tubular loop (1) fixed by its two ends (2) to a support block (3) and is provided with an oscillation generator (4) and lateral sensors (5), which convert mechanical oscillations of the loop (1) into analog electrical signals of alternating voltage. A twin-channel electronic circuit is associated with the mass flow meter, said circuit forming from the alternating voltage signals a measurement signal proportional to the mass flow. In order to improve measurement accuracy, the cartesian components of the signal vectors are determined and evaluated in connection with a digital Fourier transform. For this purpose, the amplitudes available are continuously converted into digital measurement values by means of an analog/digital converter (12), on the basis of alternating voltage signals with a predefined sampling frequency. They are then fed to a micro-computer which subjects the digitalized values to a Fourier transformation by multiplying them with the sine and cosine values corresponding to the sample and by adding these products according to a Fourier transform. The micro-computer (14) supplies a sampling frequency which is a multiple of the frequency of the alternating voltage signals, and controls the sample in such a manner that the products stored over a predefined period are constantly completed, for each sample, by a new product and the oldest product in the computer is subtracted.